1. Field of the Invention
This invention relates to a hydraulic control device for an automatic transmission to be mounted on an automobile and, more specifically, to a reverse engage preventing device operative in forward running which prevents reverse-engagement even when a shift lever is placed in reverse range in forward driving.
2. Description of the Prior Art
In general, one prior art system employs a designated solenoid valve and another additionally utilizes a 1-2 shift valve as the reverse engage preventing device in forward running.
The system using the designated solenoid valve requires many expensive solenoid valves, which increase the cost of an automatic transmission and decrease reliability.
In the system additionally using the 1-2 shift valve the operating frequency of the 1-2 shift valve increases, so that undesirable valve-sticking may occur.